Hi RustyChain, I live in Wisconsin, 105 kilos, and only have beach training along Lake Michigan so far. Hope to go to to South Padre later this week to get some water lessons. My mentor advised me to buy a used Cabrina 12M Switchblade(LOTS of patches), bar, helmet, wetsuit, booties, Fusion harness ...

I'm heavier than most, and what seems to work good is a 17-19 for the bottom end and then an 11/12 for when the wind is upper teens through mid twenty's.
I also have a 14 for when it's blowing mid teens and I don't feel like riding the 17.